Contrast agents used in angiography procedures for patients with cardiovascular disease are known to cause contrast-induced nephropathy (CIN), which may be partially due to the production of nephrotoxic oxygen-free radicals. It is uncertain whether administration of intravenous (IV) anti-oxidant, N-acetylcysteine (NAC), can prevent reduction in renal function and whether this is a cost-effective approach.

Sixty-five day-only patients with renal impairment (mean serum creatinine concentration 0.16±0.03mmol/l) due to undergo coronary or peripheral angiography and/or stenting were randomly assigned to IV NAC 300 or 600mg immediately before and after the procedure or IV fluid alone.

Of the 60 patients with complete data, none had acute CIN (increase in serum creatinine concentration ≥0.044mmol/l, 48h after administration of contrast agent). Eight patients (13%) have demonstrated an increase in their serum creatinine concentration ≥0.044mmol/l 30 days after administration of contrast agent: 2/19 (11%) in the control group, 2/21 (10%) in the 600mg NAC group and 4/20 (20%) the 300mg NAC group (p=0.66). The mean volumes of contrast agent used and prehydration given for each of the three groups did not differ significantly (p>0.83). There was significant improvement in creatinine clearance within each group from baseline to 30 days (p≤0.03), but no significant difference between the groups at 48h and 30 days (p≥0.43). Considering the cost of NAC and its administration, we estimate that this would translate to a saving of $26,637 per annum.

For day-stay patients with mild-to-moderate chronic renal impairment undergoing angiography and/or intervention, prehydration alone is less complicated and more cost-effective than a combination of IV NAC (at doses used) and hydration.